Advanced Materials Research Vols. 374-377

Abstract: The tensile test specimens of ETFE (ethylene - tetrafluoroethylene copolymer) membrane have been done at 7 temperatures. It is obtained corresponding stress - strain tensile curve, tensile strength and breaking elongation. Through experiments, it is given the tensile curves at different temperatures to determine turning points on the two rigid method, which has been a turning point corresponding to the yield stress and strain; and it is given ETFE calculation of elastic modulus by tensile curve calculate the tangent modulus, secant modulus, elastic modulus of the second and third; through numerical calculation, it is measured the energy performance of ETFE membranes. The results of the experiments provide a theoretical basis of ETFE membrane to study the architecture.

Abstract: The spheroidization of the carbide of hot-deformed GCr15 bearing steel was investigated in cyclic annealing process. The results show that most of carbide particles become gradually smaller and more dispersed with the increase of process cycle, however, part of them start to grow for the four cycles, the growth agrees well with Ostwald Ripening Law, and it is not suitable for the further process.

Abstract: Based on the necessary relationship between the strength and the water content of unsaturated soil, combined with real foundation pit in unsaturated soil, firstly, physical and mechanical parameters of soil samples with different water content are obtained through triaxial test. Secondly, the computation model is built by using PLAXIS, and numerical analyses of deformation characteristic in deep foundation pit are performed, then, the relation curves between water content and deformation values are plotted, which include ground deformation, support pile deformation and upheaval deformation at pit bottom, meanwhile, the influence laws of soil water content on deformation characteristic are summed up. The case study show that soil water content is a key influence factor for deformation characteristic of deep foundation pit in unsaturated soil, and the research results have some theoretical meaning and practical value for design and construction of deep foundation pit.

Abstract: The paper studied on the mix design method of two different warm mix asphalt adopted Marshall test and SGC(Superpave Gyratory Conpactor) test, and analysed their differences of high temperature stability, low temperature cracking resistance performance. The results show that, for different types of warm mix asphalt, it should be taken a different test method to design. It was recommended that the design of warm mix asphalt based on surface activity agent should use Marshall method, and warm mix asphalt with the addition of organic agent should use SGC method.

Abstract: A method for determining the coefficient of thermal expansion (CTE) of concrete with optical lever system is introduced. In order to improve the system of traditional optical lever, vernier caliper was used instead of the scale plate to deduce the precise formula according to theories. The experiment was carried out to test the CTE of concrete with different aggregates. The results show that: when aggregate content was equivalent, the CTE of concrete increased with that of aggregate. Type of aggregate affected the CTE significantly.

Abstract: In order to investigate the mechanical behaviors of lime-stabilized soils with small lime content, the specimens with 4%~8% lime content and 90%~95% degree of compaction are prepared, and then in use for the unconfined compression strength test, the diametral compression test and the compression resilience modulus test after they have cured in a standard curing room for 7 to 180 days respectively. These test results show that all of the unconfined compression strength, the splitting strength and the compression modulus of resilience increase with the degree of compaction and the curing time. Thereinto, the compression modulus of resilience does rapidly between 28 and 90 curing days, and the unconfined compression strength of the soil with 4% lime content does little after 28 curing days while the compression strengths and the splitting strengths of the other soils do quickly until 90 curing days. In addition, for a given degree of compaction, these strengths of the soils with the less lime content are potentially greater at the early curing time.

Abstract: This paper focuses on the impact which polypropylene fiber (PF) has on the self-desiccation effect at early age of high performance concrete (HPC). The experimental results indicate that PF has little influence on the Internal Relative Humidity (IRH) caused by self-desiccation effect of concrete, but can reduce early aged self-desiccation shrinkage of concrete. With the PF dosage increasing, the values of early self-desiccation shrinkage of HPC decrease first and then increase. In the experimental conditions, the value of self-desiccation shrinkage of concrete with 0.6Kg/m3 PF is the lowest one.

Abstract: This experimental research was to investigate the chloride penetration and consolidation behavior of OPC and coal gangue added cement. By comparing the results of two kinds of cement, results showed that the chloride consolidation of gangue added cement is higher than OPC. The chloride consolidation increased with more gangue added. The coal gangue is helpful to impede the chloride ingress until the added content reach 30%. The more gangue content decreased the fluid of mortar. And this increased the porosity of harden pastes. Furthermore the corrosion behavior of steel bar in OPC and G30 samples were conducted. Corrosion potential of gangue added cement moved positively comparing with OPC. These indicated that the propriety gangue content was helpful to steel bar protection.

Abstract: In order to obtain the high performance cement-based consistent materials，the enhancement effect of basalt fiber was studied to develop the building mortar with a high flexural strength . Three factors such as basalt fibers fraction，water-cement ratio and sand-lime ratio are studied on compressive and flexural strength on 7 days and 28 days through the orthogonal experimental design and statistical analysis. According to project needs, the best combination of flexural strength is optimized. The enhancement mechanism and damage features are analyzed and evaluated by SEM, the result shows that the basalt fiber as enhanced component have a very good flexural strength enhancement effect, the maximum increased rate will reach 2.91 times. The effect on the strength of different age period is remarkable with different fiber fraction which is far greater than the water-cement ratio and sand-lime ratio. Basalt fiber have better physical and mechanical properties and better alkali resistance, some performance are second only to carbon fiber, and the cost of basalt fiber is far lower than carbon fiber, So the basalt fiber have a broad application prospects in the field of cement-based composite materials.

Abstract: The fractal characteristics of concrete materials microstructure are analyzed with fractal theory. The fractal dimension of concrete materials microstructure in the different conditions are tested and counted by code and box Dimension. The result shows that the fractal characteristics of concrete materials microstructures are highly notable, as interface of cement clinker mineral, dispersed state of unhydrated cement particles, crack of hardened cement paste, hydration product and pore structure of hydrated cement paste section. Proving it is effective to measure surface of cement clinker mineral, figures of hydration C-S-H grains and outlines, pore structure of concrete section. Using box dimension is effective to test microcracks and pore structure of section of motor samples and fiber-hydrate. In the course of fractal analysis, the dimensions of fractal are bigger than their topologic dimension, and they are smaller than their space dimension, they are keeping with the fractal theory.